I honestly have never used primer before. I somehow went down a rabbit hole when this plus a Lancôme mascara were recommended on Amazon after I purchased lash growth serum. I got the “trial” size of this primer and the Monsieur Big mascara and wow… I am never using another mascara again. The mascara alone is great, but this primer makes it so much better. I have pencil straight lashes that I have to over curl because mascara wets down the curl and makes them straight again. I keep a small fan close to help dry quicker to keep the curl. With the primer I apply it, use the fan for a few seconds on my lashes, then apply the mascara, and use the fan until dry. My photo shows the difference the primer makes even with the mascara (ignore my overgrown brows.) It lengthens and keeps my lashes separated. I also find it easier to apply the mascara if I use the primer. I highly recommend this!